- 學位論文
使用功率量測器自動化追蹤超音波探頭頻率響應之驅動器
Automatic resonance frequency tracking driver for ultrasonic transducers using a power meter
摘要
目前醫學上相關超音波探頭的研究所使用超音波探頭因其應用而有不同的頻率，一般欲驅動超音探頭必須用手調方式找到適合探頭的工作頻率，此方式既不方便且不精準。然而換能器在適合的工作頻率，功率會較大，因此本研究欲設計一系統具自動化給於換能器適合及精確的工作頻率，避免換能器長期在不適合的頻率因而造成損壞。 首先使用C++語言上載至Arduino UNO 微控制板傳送AD5930 開發的函數發生器，產生連續或者脈衝串的波形以及調整輸出信號的頻率、觸發時間等參數。由於長期的使用超音換能器將承受過熱，本系統欲使用突發波形可以防止換能器因過熱損壞。將其輸出信號送至Inverter 連接至一可調電源供應器再依其不同超音波換能器所需的信號加以調整強度，通過諧波濾波器降低諧波分量，以利於取得近似正弦的電壓波形輸出給超音波換能器。 再經由本研究所設計之功率量測器作為監測系統，將功率訊號送回AD5930 結合Arduino 所編程的訊號產生器去做訊號處理判讀及給予驅動適合換能器的工作頻率，此裝置較以往操控方式容易且攜帶方便，大幅增加使用者在使用上的便利性。
並列摘要
The Current research relates to ultrasound probes, which according to their application use different frequencies. In general, driving an ultrasound probe must find a suitable way to manually adjust the operating frequency of the probe, but it’s not convenient and accurate. However, in a suitable operating frequency, its power will become higher. Therefore, in this study, we designed a system that can adjust to a suitable and accurate operating frequency automatically. In this study, we developed a function generator using an AD5930 which can produce continuous or burst waveforms. The use of burst waveforms can prevent damage caused by overheat. The output signal is then fed to the inverter to adjust the signal amplitude according to the power supply voltage and drive the ultrasound transducer. A C++ produced software was used to upload parameters to an Arduino UNO microcontroller board so that it can program the AD5930 burst waveform generator to adjust the parameters of the output signal such as the frequency and the burst time. Using this hardware and software concept applied on different ultrasound transducers, we expect to expand the application of ultrasound transducers in the biomedical field. An Arduino microcontroller combined with the AD5930 circuit produces output digital and/or analog signals with stable frequency. The user can easily and conveniently adjust to a desired fixed output frequency or set an increasing sweep frequency. This type of device could be used in various ultrasonic probe applications.